Erik Johnson Rumors

The Mariners have called up left-hander James Paxton, Don Ruiz of the Tacoma News Tribune reports. Paxton, 24, was ranked before the season as one of the game's top prospects by MLB.com (57th) and Baseball America (#87) and he has posted a 4.45 ERA, 8.1 K/9, 2.26 K/BB rate over 145 2/3 innings in his first taste of Triple-A this year. The southpaw is the second top M's pitching prospect this week to receive a promotion, afterTaijuan Walker. Paxton is under team control through the 2019 campaign and he'll have to be added to Seattle's 40-man roster.

The Brewers have called up right-hander Jimmy Nelson, manager Ron Roenicke told reporters (including MLB.com's Adam McCalvy). Nelson, a second-rounder from the 2010 draft, has been a starter for the last three seasons but the Crew will use him as a reliever. MLB.com ranked Nelson as the top prospect in the Brewers system and the 88th-best prospect overall, saying that the 24-year-old has "a heavy fastball that elicits ground balls and sits in the low 90s." Nelson posted a 3.25 ERA, 9.6 K/9 and 2.51 K/BB rate in 27 starts at Double-A and Triple-A this season, though he didn't perform quite as well at Triple-A. Since he's being called up at this late date in the season, Nelson won't gain Super Two status and will be under team control through 2019.

The Orioles have called up middle infielder Jonathan Schoop, according to David Hall of the Virginian Pilot (Twitter link). Schoop was ranked as the 50th-best prospect in baseball by ESPN's Keith Law (ESPN insider subscription required) before the season and MLB.com ranks him as the fourth-best prospect in the Baltimore organization. Schoop, 21, hails from Curacao and has gradually evolved from a shortstop to a second baseman over his five minor league seasons could possibly be Brian Roberts' replacement at the position in the Major Leagues. Schoop was limited to 285 PA at Triple-A Norfolk this season due to a stress fracture in his back, and he hit .255/.298/.397 with nine homers for the Tides. He will be under team control through 2019, as Schoop's late callup won't give him Super Two status. Besides Schoop, the O's have also called up Henry Urrutia and right-hander Josh Stinson.

As expected, the Reds have purchased the contract of outfielder Billy Hamilton, according to a tweet from his now-former club, the Triple-A Louisville Bats. Hamilton currently stands as the 17th-best prospect in baseball, according to MLB.com's Jonathan Mayo. The 22-year-old burner has scuffled somewhat in his first season at Triple-A, seeing his on-base percentage drop to a career-low .308 mark and carrying a .651 OPS. Nevertheless, he has swiped 75 bases in 90 attempts, added some pop (he has a career-best six home runs), and transitioned from shortstop to center field. Baseball Prospectus has a full scouting report on Hamilton (subscription required) as he reaches the bigs for the first time.

The White Sox have brought up two of the organization's top prospects, Dan Hayes of CSNChicago.com tweets. In addition to well-regarded youngster Marcus Semien, the club has purchased the contract of righty Erik Johnson, who John Sickels of Minor League Ball ranks as the 76th-best prospect in the game. Though he missed the top-100 list of MLB.com's Jonathan Mayo, Johnson did appear at the number two slot among White Sox prospects, with Mayo explaining that he has the repertoire to become a mid-rotation starter. The 23-year-old has an excellent 1.57 ERA over 57 1/3 innings since reaching Triple-A, where he maintains a 8.9 K/9 ratio against 3.0 BB/9.

If you're a moderate to hardcore baseball fan, you've probably heard of the term "Super Two" when top prospects and their imminent big league promotions are being discussed. Basically, it's an important business aspect of baseball that can cause your favorite MLB-ready prospect to spend a little extra time in the minors. For a refresher on the subject, check out Tim Dierkes' article from April and Ben Nicholson-Smith's post from February.

Now that you're up to date and understand why some players have been recently called up to the Majors, it's time to identify the next big-named prospects who could be promoted in 2013, following in the footsteps of the Rays' Wil Myers, the Mets' Zack Wheeler, and the Mariners' Mike Zunino.

Xander Bogaerts, SS, Red Sox: Bogaerts, 20, didn't let his age stop him from dominating Double-A ball. One of the youngest players in the Eastern League, the shortstop hit more than .300 with strong on-base skills and power. The Aruba native earned himself a trip to Triple-A after less than half a season. A strong start to 2013 earned fellow shortstop prospect (and potential roadblock) Jose Iglesias a 25-man roster spot as the backup to oft-injured veteran Stephen Drew, but Bogaerts has a much higher ceiling. Iglesias is much more likely to end up as trade bait thanks to his high-level play — should Boston need to shore up its roster for a run at the playoffs. Drew is a free agent at the end of the year, and the Red Sox may want to give Bogaerts a chance to get his feet wet in the Majors by the end of the year to gauge if he's truly ready to assume the full-time gig in 2014.

Nick Castellanos, 3B/OF, Tigers: Castellanos had a modest start to the 2013 season, but he's seen his offensive numbers improve each month with his OPS rising from .755 to .814 to 1.025. Also working in his favor for a call-up is the fact that he can offer competent defensive assistance at both third base and in the corner outfield. Miguel Cabrera isn't going to be bumped from his starting gig at the hot corner, but the emergence of Castellanos could allow the club to rest the veteran in the second half of the year in preparation for long playoff run. The prospect could also be a solid platoon complement to left fielder Andy Dirks, a left-handed hitter. It would also give Avisail Garcia — another rookie outfielder — a chance to spend more time in Triple-A. Lynn Henning of the Detroit News wrote that Castellanos could be a key player for the big league club as it tries to secure a playoff spot in 2013.

Sonny Gray, RHP, Athletics: Aside from Bartolo Colon, injuries have ensured that Oakland's starting rotation lacks pitchers with more than two years of service time. Due to the volatility of young pitchers, depth could become an issue for the first-place club in the second half of the year. Gray, a former first round draft pick, could offer some help after rebounding well from a disappointing 2012 season. The right-hander has averaged more than six innings per start in his 13 Triple-A appearances and struck out 83 batters in 82 1/3 innings of work.

Erik Johnson, RHP, White Sox: Chicago is currently deploying an inexperienced starting rotation with the likes of Hector Santiago, Jose Quintana, and Dylan Axelrod. Johnson, a former second round draft pick, has dominated pro ball and his time at Double-A in 2013 has been no different. He currently has a 2.24 ERA with 74 strikeouts and just 21 walks in 84 2/3 innings of work. Johnson, 23, has a frame that suggests he should develop into an innings-eater and his pitching acumen could eventually help him develop into a No. 2 or 3 starter for the Sox. The California native could offer some assistance to the big league club in the second half of the season, and he has the highest ceiling of any starter in the Sox system at either Double-A or Triple-A. Mark Gonzales of the Chicago Tribune recently penned an article after speaking with Johnson, who said he's just taking it one day at a time and not worrying about a promotion to The Show.

Danny Salazar, RHP, Indians: After spending big in the offseason, Cleveland finds itself in a playoff hunt. With a big league starting rotation that features some rather large question marks with the likes of Ubaldo Jimenez, Scott Kazmir, and Carlos Carrasco, Salazar could become a key player at some point during the second half of the season. While splitting the season between Double-A and Triple-A, the Dominican right-hander has struck out 80 batters in 58 innings of work. If he doesn't figure into the club's plans in the starting rotation, his power arsenal and ability to pitch multiple innings could allow him to offer some assistance in the bullpen in the latter half of the year and even the playoffs. In a piece for MLB.com, John Wagner spoke to Salazar's Triple-A manager, Chris Tremie, who talked about the things that the young pitcher does well.

Jonathan Singleton, 1B/OF, Astros: Singleton's season got off to an inauspicious start when he was suspended for 50 games after violating minor league baseball's drug policy. Since returning, the 21-year-old hitter has appeared in just 10 games, split between Single-A, Double-A and now Triple-A. Thirteen of his 20 hits have gone for extra bases, and he's walked 13 times. Singleton has experience playing both left field and first base but has exclusively played the infield in 2013. Despite that, his clearest opening for big league playing time could be in the outfield where Trevor Crowe, J.D. Martinez, and (recently demoted) Jimmy Paredes have produced less-than-impressive numbers. First basemen/designated hitters Chris Carter and Carlos Pena have also had underwhelming seasons to date (and could become trade bait) but offer much-needed power. The playoffs are out of the question for 2013, but once outfield prospect George Springer joins Singleton in Houston, the club will have a strong middle-of-the-order core to build around.

Yordano Ventura, RHP, Royals: Talented but undersized pitching prospects are slowly shedding the stigma that they're destined for future bullpen work at the big league level. Like Toronto's Marcus Stroman, the slender Ventura doesn't break the six-foot mark, but his upper-90s velocity — which tickles triple digits — has intrigued prospect watchers since he came over to North America from the Dominican Republic in 2010. After opening 2013 in Double-A, a recent promotion has brought Ventura one step away from the Majors. Should injuries strike — or should the Royals tire of the inconsistent performances from Luis Mendoza or Wade Davis — the 22-year-old Dominican could receive the call. Jeffrey Flanagan of Fox Sports Kansas City recently spoke to Royals Assistant General Manager J.J. Picollo who said the organization is looking to have Ventura become more efficient and keep his pitch counts down.